Yellow fever (YF), Chikungunya (CHIK), and Zika(ZIK) are among re-emerging arboviral diseases of major public health concern. Despite the proximity of the Gambella Region to South Sudan where arboviral cases have been recorded repeatedly... more
Yellow fever (YF), Chikungunya (CHIK), and Zika(ZIK) are among re-emerging arboviral diseases of major public health concern. Despite the proximity of the Gambella Region to South Sudan where arboviral cases have been recorded repeatedly the current epidemiological situation is unclear in this part of southwest Ethiopia. Therefore, we conducted a community-based seroprevalence survey of YF virus (YFV), CHIK virus (CHIKV), and ZIK virus (ZIKV) infections in two selected districts. A cross-sectional study was conducted in two locations of the Gambella region (Lare and Itang) to investigate the seroprevalence of these viruses’ infections. Blood samples were collected from the study participants and screened for IgG antibodies specific to YFV and CHIKV infections using enzyme-linked immunosorbent assays (ELISA). For the detection of ZIKV specific IgG antibodies, Blockade-of-binding ELISA was used. Data were analyzed using the STATA version 13.1 Softwares. A total of 150 individuals (96 ...
Research Interests:
Background: Staphylococcus aureus is one of the predominant causative agents of mastitis disease in dairy herds. Mastitis disease has a negative impact in the economic losses in the dairy sector across the globe. The aims of this study... more
Background: Staphylococcus aureus is one of the predominant causative agents of mastitis disease in dairy herds. Mastitis disease has a negative impact in the economic losses in the dairy sector across the globe. The aims of this study were to determine the prevalence and detect antimicrobial resistance genes in the Staphylococcus aureus isolated from milk samples of subclinical bovine mastitis in Central Ethiopia.Methods: A total of 265 lactating dairy cows from various dairy farms in four different geographical locations were screened by California mastitis test (CMT) for bovine subclinical mastitis. One-hundred thirty CMT positive milk samples were collected and transported to laboratory. Different biochemical tests and polymerase chain reaction (PCR) were used for the identification of S. aureus isolates. Finally, phenotypic and genotypic methods were performed for detection of some antimicrobial resistance patterns and genes (mecA, ermA, ermC, and msrA), respectively. Results: ...
Research Interests:
A cross-sectional study was carried out on randomly sampled 384 animals to assess the occurrence of small ruminant brucellosis and risk factors contributing for the zoonotic potential of the disease at Dallo-Manna and HarannaBulluk... more
A cross-sectional study was carried out on randomly sampled 384 animals to assess the occurrence of small ruminant brucellosis and risk factors contributing for the zoonotic potential of the disease at Dallo-Manna and HarannaBulluk districts of Bale Zone. Rose Bengal plate test (RBPT) and complement fixation test (CFT) were used serially. All collected serum samples were subjected to RBPT first and then positive sera with RBPT were further tested for confirmation using CFT. Animal level prevalence of 6.5% and 2.9%, and flock level prevalence of 50% and 22% were recorded by RBPT and CFT respectively. Flock level prevalence at Dallo-Manna is 3.8-fold (95% OR CI = 1.17-12.19) than at Haranna-Bulluk (95% OR CI = 0.32-3.31) but no statistical significant difference (p>0.05). The Chi-square (χ2) statistical analysis indicated that age (χ2=6.18; p<0.05), parity (χ2=0.57; p<0.05), retained fetal membrane (χ2=35.5; p<0.001) and abortion history (χ2=45.1; p<0.001) were associat...
There is paucity of information in the epidemiology and pathology of tuberculosis in swine though the endemic occurrence of bovine tuberculosis was elucidated in Ethiopia. A cross-sectional study was employed to investigate the... more
There is paucity of information in the epidemiology and pathology of tuberculosis in swine though the endemic occurrence of bovine tuberculosis was elucidated in Ethiopia. A cross-sectional study was employed to investigate the epidemiology of Mycobacterium tuberculosis complex and Mycobacterium avium complex in swine. The study was conducted from September 2016 to December 2017 using single intradermal comparative tuberculin test, gross pathology and histopathology. Tuberculin test was carried out in farmed swine of central Ethiopia while the necropsy at Addis Ababa Abattoirs Enterprise, Ethiopia. Of the total 329 heads of swine tuberculin tested by bovine purified protein derivative antigen, an animal level prevalence of 3% (95% CI: 2-6) and a herd level prevalence of 11% (95% CI: 1-49) were observed at a cut-off value of >2mm. Multivariable logistic regression analysis revealed the protective exposure effect of body condition to tuberculin test positivity in swine (Adjusted O...
A cross-sectional survey was conducted to estimate the incidence of small ruminant abortion and identify its major causes and potential risk factors in goat and sheep flocks in three agroecology and production systems of Ethiopia.... more
A cross-sectional survey was conducted to estimate the incidence of small ruminant abortion and identify its major causes and potential risk factors in goat and sheep flocks in three agroecology and production systems of Ethiopia. Information on pregnancy outcomes and management risk factors were collected for 299 goat and 242 sheep flocks. Blood samples were collected from 133 sheep and 90 goat flocks and tested for Coxiella burnetii, Brucella spp., Chlamydia abortus, and Toxoplasma gondii. A causal diagram outlined relationships between potential predictor variables and abortion in the flock. The effect of management and exposure to infectious causes on the number of abortions in the flock across agroecology was tested using zero-inflated negative binomial regression. Results showed that 142 (58.68%) goats and 53 (17.73%) sheep flocks reported abortions in the 12 months before the survey. The mean annual flock abortion percentages were 16.1% (±26.23) for does and 12.6% (±23.5) for...
Background: Brucellosis is one of the most important reproductive disease causes abortion and breeding failure in small ruminants and also causes severe systemic diseases in exposed humans. In Ethiopia, several studies of seroprevalence... more
Background: Brucellosis is one of the most important reproductive disease causes abortion and breeding failure in small ruminants and also causes severe systemic diseases in exposed humans. In Ethiopia, several studies of seroprevalence shows the magnitude and distribution of brucellosis both in animals and humans vary in different geographical localities. However, except few studies in Ethiopia all these serological studies was limited to RBPT and CFT, so far not supplemented with a varities of serological tests like ELISA to detect brucella infection, which is increase the likehood of detecting infected individulas and also improve the reliability of epidemiological data for appropriate control strategies. Hence, the present study was conducted in Amibara district of Afar Region, Ethiopia to detect the seropositivity and risk factor of Brucella infection in small ruminants that had history of recent abortion using mRBPT, cELISA and CFT. Materials and methods: Sera were collected f...
Bovine tuberculosis (bTB) is a serious infectious disease of cattle with significant economic impact and public health risk. It is particularly important in Ethiopia where effective control measures are lacking. This cross-sectional study... more
Bovine tuberculosis (bTB) is a serious infectious disease of cattle with significant economic impact and public health risk. It is particularly important in Ethiopia where effective control measures are lacking. This cross-sectional study was carried out between April and July 2016 on 1038 cattle selected from 206 dairy farms in Adama city located in central Ethiopia to estimate the prevalence of bTB and identify the potential risk factors using comparative intradermal tuberculin skin test. Accordingly, the individual animal level prevalence was found to be 2.1% (95% CI: 1.35 – 3.22). Of the 206 dairy farms included in the study, 7.3% (95% CI: 4.29 – 11.98) had one or more 15 cattle positive for the tuberculin test. Furthermore, 5.5% of the examined cattle were found reactive for atypical Mycobacterium. Among the risk factors considered, age and lactation status of the animals were significantly associated (p< 0.05) with the prevalence of bTB. It was noted that the apparent preva...
A cross-sectional abattoir-based study was conducted in apparently healthy chicken in Bishoftu town, Ethiopia to estimate the prevalence of avian tuberculosis and isolate its causative agent. The occurrence of avian tuberculosis was... more
A cross-sectional abattoir-based study was conducted in apparently healthy chicken in Bishoftu town, Ethiopia to estimate the prevalence of avian tuberculosis and isolate its causative agent. The occurrence of avian tuberculosis was investigated using postmortem examination, bacteriological culture and acid-fast staining methods. Of the total 648 chicken examined to detect avian tuberculosis, 42 tissue samples showing gross pathological tuberculous-like lesions were collected from liver, spleen and intestine. The overall prevalence of avian tuberculosis in poultry was 6.48% (42/648) (95%CI: 4.53-8.38) on the basis of detailed postmortem examination. Out of 42 tissue samples cultured on Lowenstein-Jensen medium, 14 (33.3%) were bacteriologically culture positive and showed growth of dough-shaped smooth colony characteristic and out of these 14 culture positive samples, 5 (35.7%) were acid-fast positive mycobacteria. Statistical significant difference was observed in the prevalence of...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
In sub-Saharan Africa, where there is the scarcity of proper diagnostic tools, febrile illness related symptoms are often misdiagnosed as malaria. Information on causative agents of febrile illness related symptoms among pastoral... more
In sub-Saharan Africa, where there is the scarcity of proper diagnostic tools, febrile illness related symptoms are often misdiagnosed as malaria. Information on causative agents of febrile illness related symptoms among pastoral communities in Ethiopia have rarely been described. In this a community based cross-sectional survey, we assessed the prevalence of typhoid fever, typhus, brucellosis and malaria among individuals with a set of given symptoms in Amibara district, Afar Region, Ethiopia. Blood samples were collected from 650 study participants, and examined by Widal and Weilfelix direct card agglutination test (DCAT) as well as test tube based titration test for Salmonella enterica serotype Typhi (S. Typhi) and Rickettsia infections. Rose Bengal Plate Test (RBPT) and Complement Fixation Test (CFT) were used to screen Brucella infection. Thin and thick blood smears were used to diagnosis malaria. Out of 630 sera screened by DCAT, 83 (13.2%) were reactive to H and/or O antigens...
Research Interests:
Research Interests:
Research Interests:
Middle East respiratory syndrome coronavirus (MERS-CoV) causes a zoonotic respiratory disease of global public health concern, and dromedary camels are the only proven source of zoonotic infection. Although MERS-CoV infection is... more
Middle East respiratory syndrome coronavirus (MERS-CoV) causes a zoonotic respiratory disease of global public health concern, and dromedary camels are the only proven source of zoonotic infection. Although MERS-CoV infection is ubiquitous in dromedaries across Africa as well as in the Arabian Peninsula, zoonotic disease appears confined to the Arabian Peninsula. MERS-CoVs from Africa have hitherto been poorly studied. We genetically and phenotypically characterized MERS-CoV from dromedaries sampled in Morocco, Burkina Faso, Nigeria, and Ethiopia. Viruses from Africa (clade C) are phylogenetically distinct from contemporary viruses from the Arabian Peninsula (clades A and B) but remain antigenically similar in microneutralization tests. Viruses from West (Nigeria, Burkina Faso) and North (Morocco) Africa form a subclade, C1, that shares clade-defining genetic signatures including deletions in the accessory geneCompared with human and camel MERS-CoV from Saudi Arabia, virus isolates ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Identification of the types of strains of Mycobacterium tuberculosis (M. tuberculosis) complex causing tuberculosis (TB) could contribute to TB control program of specific geographic region as well as it could add knowledge onto the... more
Identification of the types of strains of Mycobacterium tuberculosis (M. tuberculosis) complex causing tuberculosis (TB) could contribute to TB control program of specific geographic region as well as it could add knowledge onto the existing literature on TB worldwide. The objective of the present study was to identify the species and strains of M. tuberculosis complex causing pulmonary tuberculosis in central Ethiopia. A health institution- based cross-sectional study was conducted on 338 smear positive TB cases visiting three hospitals between October 2012 and September 2013. Morning and spot sputum samples were collected before the starting of treatment regimens. Thus, a total of 338 pooled sputum samples collected from these cases. Samples were cultured on Löwenstein Jensen media and the isolates were identified by the region of difference (RD) 9 based polymerase chain reaction (PCR) and spoligotyping. Of the total isolates 98.6% of the isolates were identified to be M. tubercul...
Research Interests:
Research Interests:
The knowledge of the diversity of strains ofMycobacterium tuberculosiscomplex (MTBC) species in a specific geographical region can contribute to the control of tuberculosis (TB). This study was conducted to identify the MTBC isolates to... more
The knowledge of the diversity of strains ofMycobacterium tuberculosiscomplex (MTBC) species in a specific geographical region can contribute to the control of tuberculosis (TB). This study was conducted to identify the MTBC isolates to the species and spoligotype international type (SIT) level by spoligotyping. A total of 168 MTBC isolates were recovered from TB patients, spoligotyped, and their patterns were compared with those of the strains registered in the SITVIT2 database. Of 168 isolates spoligotyped, 89 patterns were identified. Ninety-eight isolates were clustered into 19 strain groups with clustering percentage of 58.3%. Forty-four strains matched the preexisting SITs in the SITVIT2 database. The dominant strains were SIT289, SIT134, and SIT3411, comprising 16.7% (28/168), 7.14% (12/168), and 4.76% (8/168) of the isolates, respectively. Euro-American (51.2%), East-African-Indian (34.5%), andM. africanum(9.52%) were the major lineages identified. Two strains ofM. boviswere...
Research Interests:
A cross-sectional study was conducted from September, 2010 to July, 2011 on 1,066 cattle (484 dairy and 582 beef) in two districts of Western Tigray Zone, Northern Ethiopia, to investigate the epidemiology of mycobacterial infections in... more
A cross-sectional study was conducted from September, 2010 to July, 2011 on 1,066 cattle (484 dairy and 582 beef) in two districts of Western Tigray Zone, Northern Ethiopia, to investigate the epidemiology of mycobacterial infections in cattle and characterize its causative agents. Comparative intradermal tuberculin (CIDT) test, pathological and bacteriological examination, and molecular typing were employed to undertake this study. The study found the animal tuberculosis (TB) reactor prevalence in dairy cattle to be 6.6% (95% CI, 4.4 to 8.8) and 8.7% (95% CI, 6.2 to 11.2) at ≥4 and ≥2 mm cut-offs, respectively, while the herd prevalence were 61.3% (95% CI, 43.1 to 79.5) at cut-off ≥4 mm and 77.4% (95% CI, 61.8 to 93.0) at cut-off ≥2 mm. On the basis of abattoir survey, the prevalence of tuberculoid lesions was 5.8% in beef cattle with the largest proportion (61.8%) of lesions recorded from the respiratory tract. Bacteria were successfully cultured from 35.3% (12/34) tissue samples;...
Research Interests:
Bovine tuberculosis (BTB) has a potential public health risk and economic impact in pastoralist community whose livelihood depends on their livestock. A cross-sectional study was carried out from September, 2008 to June, 2011 on 1087... more
Bovine tuberculosis (BTB) has a potential public health risk and economic impact in pastoralist community whose livelihood depends on their livestock. A cross-sectional study was carried out from September, 2008 to June, 2011 on 1087 cattle under pastoral and agro-pastoral production system in four districts of Afar Pastoral Region of Ethiopia using comparative intradermal tuberculin skin test to estimate the prevalence of BTB and assess the associated risk factors for infection. The individual animal prevalence of BTB in cattle of Afar pastoralists was 11% (95% confidence interval (CI): 9 to 13%) with ≥ 4 mm cut-off and 18% (95% CI: 16% to 21%) with ≥2 mm cut-off. The herd prevalence was 44% (95% CI: 36 to 51%) and 56% (95% CI: 48 to 63%) at ≥4 and ≥2 mm cut-off points, respectively. In bivariate analysis, the prevalence was significantly associated with study districts, herd size, sex and age, and in multivariable logistic regression analysis, the statistical significance was main...
The study was conducted to estimate the prevalence of avian tuberculosis (TB) and assess associated risk factors in Shashemene District. In addition, the zoonotic implication of avian tuberculosis in the District was investigated. In this... more
The study was conducted to estimate the prevalence of avian tuberculosis (TB) and assess associated risk factors in Shashemene District. In addition, the zoonotic implication of avian tuberculosis in the District was investigated. In this study, 260 adult domestic chickens of both sexes were tested by tuberculin test on their wattle. Test positive chickens were sacrificed and examined for the presence of tuberculous lesion. Suspicious lesions were cultured for mycobacterial isolation and characterization using multiplex polymerase chain reaction (PCR). On top of these, questionnaire was used to assess public perception and the potential public health risks of the disease. The prevalence of avian TB at Shashemene District was 4.23% (11/260). Gross TB lesions were detected in six of the 11 tuberculin positive chickens. Culture positivity was confirmed in three of the chicken with gross lesions. These isolates were confirmed to be members of the Genus Mycobacterium. Multivariable logis...
Research Interests:
Little attention has been given to the role of antibodies against Mycobacterium tuberculosis (Mtb) infection. We have compared the levels of IgA and IgG against ESAT-6/CFP-10 and Rv2031c antigens in sera of patients with culture-confirmed... more
Little attention has been given to the role of antibodies against Mycobacterium tuberculosis (Mtb) infection. We have compared the levels of IgA and IgG against ESAT-6/CFP-10 and Rv2031c antigens in sera of patients with culture-confirmed pulmonary tuberculosis (PTB), healthy Mtb-infected and non-infected individuals in endemic TB settings. Venous blood samples were collected from 166 study participants; sera were separated and assayed by an enzyme-linked immunosorbent assay (ELISA). QuantiFERON-TB Gold In-Tube (QFTGIT) assay was used for the screening of latent TB infection. The mean optical density (OD) values of IgA against ESAT-6/CFP-10 and Rv2031 were significantly higher in sera of patients with culture-confirmed PTB compared with healthy Mtb-infected and non-infected individuals (P &amp;amp;lt; 0.001). The mean OD values of IgG against ESAT-6/CFP-10 and Rv2031 were also significantly higher in sera of patients with culture-confirmed PTB compared with healthy Mtb-infected and non-infected individuals (P &amp;amp;lt; 0.05). The mean OD values of IgA against both antigens were also higher in sera of healthy Mtb-infected cases compared with non-infected individuals. There were positive correlations (P &amp;amp;lt; 0.05) between the level of IFN-γ induced in QFTGIT assay and the OD values of serum IgA against both antigens in healthy Mtb-infected subjects. This study shows the potential of IgA response against ESAT-6/CFP-10 and Rv2031 antigens in discriminating clinical TB from healthy Mtb-infected and non-infected cases. Nevertheless, further well-designed cohort study is needed to fully realize the full potential of this diagnostic marker.
Research Interests:
The study was conducted to estimate the prevalence of avian tuberculosis (TB) and assess associated risk factors in Shashemene District. In addition, the zoonotic implication of avian tuberculosis in the District was investigated. In this... more
The study was conducted to estimate the prevalence of avian tuberculosis (TB) and assess associated risk factors in Shashemene District. In addition, the zoonotic implication of avian tuberculosis in the District was investigated. In this study, 260 adult domestic chickens of both sexes were tested by tuberculin test on their wattle. Test positive chickens were sacrificed and examined for the presence of tuberculous lesion. Suspicious lesions were cultured for mycobacterial isolation and characterization using multiplex polymerase chain reaction (PCR). On top of these, questionnaire was used to assess public perception and the potential public health risks of the disease. The prevalence of avian TB at Shashemene District was 4.23% (11/260). Gross TB lesions were detected in six of the 11 tuberculin positive chickens. Culture positivity was confirmed in three of the chicken with gross lesions. These isolates were confirmed to be members of the Genus Mycobacterium. Multivariable logis...
Research Interests:
Mycobacterium tuberculosis (Mtb) persists in a state of non-replication or stationary phase, but resulting in active tuberculosis (TB) when the immune system is suppressed. Alpha-crystallin (ACR) is one of the bacterial antigens... more
Mycobacterium tuberculosis (Mtb) persists in a state of non-replication or stationary phase, but resulting in active tuberculosis (TB) when the immune system is suppressed. Alpha-crystallin (ACR) is one of the bacterial antigens characterized known to be related to shifting of the bacilli from growth to a non-replicating persistent state. To compare the ex-vivo responsiveness of active TB patients, close household contacts and healthy controls to specific Mtb antigens. Antigen-specific interferon-gamma (IFN-g) responses were measured to a 16kDa-alpha crystallin (ACR) antigen along with its peptides and other Mtb antigens (ESAT-6, CFP-10, PPD, TB10.3 and Ag85A) in 39 active TB patients, 23 close household contacts and 25 community controls, using ex-vivo ELISPOT RESULT: The proportion of responders to ACR was 36% in active TB patients (76 +/- 14 spot forming cells), 48% in close household contacts (123 +/- 31 spot forming cells) and 76% in community controls (165 +/- 29 spot forming ...
Research Interests:
Research Interests:
A cross sectional study was conducted on 2231 small ruminants in four districts of the Afar Pastoral Region of Ethiopia to investigate the epidemiology of tuberculosis in goats and sheep using comparative intradermal tuberculin skin test,... more
A cross sectional study was conducted on 2231 small ruminants in four districts of the Afar Pastoral Region of Ethiopia to investigate the epidemiology of tuberculosis in goats and sheep using comparative intradermal tuberculin skin test, postmortem examination, mycobacteriological culture and molecular typing methods. The overall animal prevalence of TB in small ruminants was 0.5% (95% CI: 0.2%–0.7%) at ≥4 mm and 3.8% (95% CI: 3%–4.7%) at cutoff ≥2 mm. The herd prevalence was 20% (95% CI: 12–28%) and 47% (95% CI: 37–56%) at ≥4 mm and ≥2 mm cut-off points, respectively. The overall animal prevalence of Mycobacterium avium complex infection was 2.8% (95% CI: 2.1–3.5%) and 6.8% (95% CI: 5.8–7.9%) at ≥4 mm and ≥2 mm cut-off points, respectively. Mycobacteriological culture and molecular characterization of isolates from tissue lesions of tuberculin reactor goats resulted in isolation ofMycobacterium tuberculosis(SIT149) and non-tuberculosis mycobacteria as causative agents of tuberculo...